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Particle agglomeration and inhibition method in the fluidized pyrolysis reaction of waste resin 被引量:1
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作者 Congjing Ren Peng Zhang +3 位作者 Qi Song Zhengliang Huang Yao Yang Yongrong Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第3期135-147,共13页
This work investigated the pyrolysis reaction of waste resin in a fluidized bed reactor.It was found that the pyrolysis-generated ash would adhere to the surface of ceramic particles,causing particle agglomeration and... This work investigated the pyrolysis reaction of waste resin in a fluidized bed reactor.It was found that the pyrolysis-generated ash would adhere to the surface of ceramic particles,causing particle agglomeration and defluidization.Adding kaolin could effectively inhibit the particle agglomeration during the fluidized pyrolysis reaction through physical isolation and chemical reaction.On the one hand,kaolin could form a coating layer on the surface of ceramic particles to prevent the adhesion of organic ash generated by the pyrolysis of resin.On the other hand,when a sufficient amount of kaolin(-0.2%(mass))was added,the activated kaolin could fully contact with the Na+ ions generated by the pyrolysis of resin and react to form a high-melting aluminosilicate mineral(nepheline),which could reduce the formation of low-melting-point sodium sulfate and thereby avoid the agglomeration of ceramic particles. 展开更多
关键词 Pyrolysis reaction of waste resin FLUIDIZATION Particle agglomeration KAOLIN
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Agglomeration of coal and polyethylene mixtures during fixed‑bed co‑gasification
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作者 Igor G.Donskoy Aleksandr N.Kozlov +2 位作者 Maksim V.Penzik Denis A.Svishchev Lu Ding 《International Journal of Coal Science & Technology》 EI CAS CSCD 2024年第2期91-100,共10页
The article presents the results of experimental studies on the gasification of mixtures of brown coal and polyethylene(up to 20 wt%fraction)in a laboratory reactor.The work aims to study the agglomeration process dur... The article presents the results of experimental studies on the gasification of mixtures of brown coal and polyethylene(up to 20 wt%fraction)in a laboratory reactor.The work aims to study the agglomeration process during the heating and oxidation of the mixtures.The measurement results(gas composition,pressure drop)provide indirect information on the dynamics of thermal decomposition and structural changes in the fuel bed.We have shown that the interaction between polyethylene and a coal surface leads to the formation of dense agglomerates,in which the molten polymer acts as a binder.Clinkers form as a result of interfacial interactions between components and filtration flow rearranging.The hydrogen/carbon ratio in the solid residue of coal-polyethylene co-gasification increases from 0.07–0.2 to 1.11,indicating the formation of stable hydrocarbon compounds on the carbon surface.The conducted research makes it possible to identify possible interactions between chemical reactions and transfer processes that lead to agglomeration in mixtures of coal with polyethylene. 展开更多
关键词 COAL POLYETHYLENE GASIFICATION Combustion agglomeration
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A new fluorocarbon adhesive:Inhibiting agglomeration during combustion of propellant via efficient F-Al_(2)O_(3) preignition reaction
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作者 Qifa Yao Min Xia +3 位作者 Chao Wang Fanzhi Yang Wei Yang Yunjun Luo 《Carbon Energy》 SCIE EI CAS CSCD 2024年第6期292-305,共14页
Inhibiting the agglomeration of molten aluminum particles packed in the binder network is a promising scheme to achieve efficient combustion of solid propellants.In this investigation,the hydroxyl-terminated structure... Inhibiting the agglomeration of molten aluminum particles packed in the binder network is a promising scheme to achieve efficient combustion of solid propellants.In this investigation,the hydroxyl-terminated structured fluorinated alcohol compound(PFD)was introduced to modify the traditional polyethylene glycol/polytetrahydrofuran block copolymerization(HTPE)binder;that is,a unique fluorinated polyether(FTPE)binder was synthesized by embedding fluorinated organic segments into the HTPE binder via crosslinking curing.The FTPE was applied in aluminum-based propellants for the first time.Due to the complete release of fluorinated organic active segments in the range of 300℃to 400℃,the burning rate of FTPEbased propellant increased from 4.07(0%PFD)to 6.36 mm/s(5%PFD),increased by 56.27%under 1 MPa.The reaction heat of FTPE propellants increased from 5.95(0%PFD)to 7.18 MJ/kg(5%PFD)under 3.0 MPa,indicating that HTPE binder modified with PFD would be conducive to inhibiting the D90 of condensed combustion products(CCPs)dropped by 81.84%from 75.46(0%PFD)to 13.71μm(5%PFD)under 3.0 MPa,in consistent with the significant reduction of aluminum agglomerates observed on the quenched burning surface of the propellants.Those results demonstrated that a novel FTPE binder with PFD can release fluorinated organic active segments,which motivate preignition reaction with the alumina shell in the early stage of aluminum combustion,and then enhance the melting diffusion effect of aluminum to inhibit the agglomeration. 展开更多
关键词 agglomeration characteristics aluminum particles COMBUSTION fluorine alcohol compounds HTPE propellants
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Evolution and Determinants of Population Agglomeration in Less Developed Metropolitan Areas:A Case Study of the Taiyuan Metropolitan Area,China
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作者 QIN Zhiqin LIANG Ye +1 位作者 AN Shuwei DOU Yongjing 《Chinese Geographical Science》 SCIE CSCD 2024年第4期739-751,共13页
It is of importance to enhance the urban areas'capacity for population aggregation in underdeveloped regions,aiming to rectify the imbalanced and insufficient pattern of economic development in China.Taking the Ta... It is of importance to enhance the urban areas'capacity for population aggregation in underdeveloped regions,aiming to rectify the imbalanced and insufficient pattern of economic development in China.Taking the Taiyuan Metropolitan Area(TMA)in central China as a case study,this paper examines the evolutionary process and characteristics of population agglomeration from 2000 to 2020,and identifies factors associated with agglomeration and their spatial effects.The findings indicated that:1)against the background of sustained population shrinkage in the provincial area,the TMA showed a demographic trend of steady increase,albeit with a decelerated growth rate.In the metropolitan area,urban population size continued to grow rapidly,whereas the rural areas endured sustained losses.Disparities in city size continued to widen,and the polarization of concentrated population in the core cities kept increasing.2)Agglomerations in both secondary and service industries had significant positive effects on local population agglomeration,with the former effect being stronger.Regional economic development,government fiscal expenditure,and financial advancement all contributed to facilitating local population clustering.From a spatial spillover perspective,service agglomeration and financial development promoted population agglomeration in surrounding areas.Conversely,fiscal expenditure inhibited such agglomeration.As for industrial agglomeration and regional economic development,their spatial spillover effects were non-significant.The results obtained reveal several policy implications aimed at enhancing the population agglomeration capacity of the metropolitan area in underdeveloped regions during the new era. 展开更多
关键词 population agglomeration population shrinkage spatial spillover effects Taiyuan Metropolitan Area(TMA) China
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Evaluation and Influencing Factors on Particle Agglomeration in RAP
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作者 唐伟 李宁 +4 位作者 ZHUANG Yuan ZHAN He YU Xin WU Wenxiu DING Gongying 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期60-68,共9页
Asphalt extraction test and scanning electron microscopy(SEM) were used for analysis of agglomerations of reclaimed asphalt pavement(RAP) particles. In order to quantify the agglomeration degree of RAP, the fineness m... Asphalt extraction test and scanning electron microscopy(SEM) were used for analysis of agglomerations of reclaimed asphalt pavement(RAP) particles. In order to quantify the agglomeration degree of RAP, the fineness modulus ratio(FMR) and the percentage loss index(PLI) were proposed. In addition, grey correlation analysis was conducted to discuss the relationship between particle agglomerations and RAP size,asphalt content(AC), and surface area. Two indexes indicate that the agglomeration degree increases in general as the RAP size reduces. This can be attributed to that particles are prone to agglomeration in the case of higher AC. Based on the SEM images and the material composition of RAP, the particle agglomeration in RAP can be classified into weak agglomeration and strong agglomeration. Grey correlation analysis shows that AC is the crucial factor affecting the agglomeration degree and RAP variability. In order to produce consistent and stable reclaimed mixtures, disposal measures of RAP are suggested to lower the AC of RAP. 展开更多
关键词 RAP particle agglomeration grey correlation analysis asphalt content
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Dynamic Development Characteristics and Driving Factors of High Quality Development Level in China’s Five Major Urban Agglomerations
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作者 ZOU Weiyong XU Lingli 《Chinese Geographical Science》 SCIE CSCD 2024年第5期777-790,共14页
High-quality development is the primary task of comprehensively building a socialist,modern country,as well as the primary task of building urban agglomerations in China.Based on the five development concepts,this pap... High-quality development is the primary task of comprehensively building a socialist,modern country,as well as the primary task of building urban agglomerations in China.Based on the five development concepts,this paper used the entropy method to measure the High Quality Development Index(HQDI)of the five major urban agglomerations.The results showed that the HQDI of the five major urban agglomerations shows a fluctuating upward trend.First,using the Dagum Gini coefficient to explore the sources of HQDI development differences in urban agglomerations,we found that the main source of HQDI differences in urban agglomerations was inter-regional differences,while intra-regional differences were not important.Second,kernel density estimation was used to test the dynamic evolution trend of HQDI within urban agglomerations.There was a polarisation phenomenon in the HQDI of urban agglomerations,such as the Pearl River Delta urban agglomeration and the Chengdu-Chongqing urban agglomeration.But overall,the degree of imbalance had decreased.Third,using geographic detectors to examine the driving factors of HQDI in urban agglomerations,we found that the main driving forces for improving HQDI in urban agglomerations were economic growth,artificial intelligence technology and fiscal decentralisation.All the interaction factors had greater explanatory power for the spatial differentiation of HQDI,which can be divided into two types:two-factor improvement and non-linear improvement.This study is conducive to improving and enriching the theoretical system for evaluating the high quality development of urban agglomerations,and provides policy references for promoting the high quality development of urban agglomerations. 展开更多
关键词 urban agglomeration High Quality Development Index(HQDI) spatio-temporal evolution driving factors
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Coupling Coordination Relationship between Ecological Human Settlements and the Happiness Levels of Residents in the Yangtze River Delta Urban Agglomeration
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作者 FAN Hua ZHAO Cuiwei 《Journal of Resources and Ecology》 CSCD 2024年第5期1251-1262,共12页
Promoting the coordinated development of ecological human settlements and the happiness levels of residents will help to promote people-centered high-quality development.This study was based on the 2011-2021 data of t... Promoting the coordinated development of ecological human settlements and the happiness levels of residents will help to promote people-centered high-quality development.This study was based on the 2011-2021 data of the Yangtze River Delta urban agglomeration,and constructed an evaluation index system of ecological human settlements and the happiness levels of residents.The entropy value method,coupling coordination degree model,Dagum Gini coefficient and Geodetector model were used to explore the coupling coordination relationship and influencing factors of these two systems.The findings indicate that ecological human settlements and the happiness levels of residents in the Yangtze River Delta urban agglomeration have shown an upward trend over time.By 2021,the overall level of the region had significantly improved.The coupling coordination level between these two systems has gradually increased,showing a spatial distribution pattern of high in the east and low in the west.The Dagum Gini coefficient shows a fluctuating downward trend in the overall and intra-regional differences,with the largest inter-regional difference between Shanghai and Anhui,and the inter-regional difference is the main source of the spatial differences.Economic development level(Eco)was the main factor influencing the coupling coordination of the two systems from 2011 to 2021.The results of this study provide references for constructing ecological human settlements and enhancing the happiness levels of residents. 展开更多
关键词 ecological human settlements happiness levels of residents coupling coordination Yangtze River Delta urban agglomeration
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Analysis of Urban Agglomeration Network Structure Based on Baidu Migration Data: A Case Study of the Guangdong-Hong Kong-Macao Greater Bay Urban Agglomeration
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作者 XIA Yuan WANG Bin 《Journal of Landscape Research》 2024年第4期47-50,共4页
The inter-city linkage heat data provided by Baidu Migration is employed as a characterization of inter-city linkages in order to facilitate the study of the network linkage characteristics and hierarchical structure ... The inter-city linkage heat data provided by Baidu Migration is employed as a characterization of inter-city linkages in order to facilitate the study of the network linkage characteristics and hierarchical structure of urban agglomeration in the Greater Bay Area through the use of social network analysis method.This is the inaugural application of big data based on location services in the study of urban agglomeration network structure,which represents a novel research perspective on this topic.The study reveals that the density of network linkages in the Greater Bay Area urban agglomeration has reached 100%,indicating a mature network-like spatial structure.This structure has given rise to three distinct communities:Shenzhen-Dongguan-Huizhou,Guangzhou-Foshan-Zhaoqing,and Zhuhai-Zhongshan-Jiangmen.Additionally,cities within the Greater Bay Area urban agglomeration play different roles,suggesting that varying development strategies may be necessary to achieve staggered development.The study demonstrates that large datasets represented by LBS can offer novel insights and methodologies for the examination of urban agglomeration network structures,contingent on the appropriate mining and processing of the data. 展开更多
关键词 Baidu migration data Social network analysis Urban agglomeration network structure Greater Bay Area urban agglomeration
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Spatio-temporal evolution of the coordinated development of high-tech industry agglomeration and resource-environmental carrying capacity in the Yellow River Basin
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作者 LI Yan REN Ai-lian +1 位作者 LI Meng-yu SUN Fan 《Ecological Economy》 2024年第3期219-236,共18页
Under the background of new infrastructure,the Yellow River Basin’s superior growth cannot be separated originating with the synergistic effect of scientific and technological inventiveness and ecological civilizatio... Under the background of new infrastructure,the Yellow River Basin’s superior growth cannot be separated originating with the synergistic effect of scientific and technological inventiveness and ecological civilization construction.In light of the coupling coordination analysis of the coordination effect of provincial high-tech industry agglomeration and resource carrying capacity in the Yellow River Basin from 2009 to 2021,The evolution of the geographical and temporal pattern of development was investigated using the Moran index and kernel density estimation.The results show that the agglomeration of high-tech industries in the Yellow River Basin presents a development trend of seek improvement in stability,and there is a good coupling and coordination throughout the progression of scientific and technological innovation and the loading capacity of the resource,from the viewpoint of a time series.From the perspective of spatial pattern distribution,the whole basin aims at the lower reaches,accelerates the optimization of digital industry and promotes Yellow River Basin development of superior quality through innovation support and increase of input,and based on policy guidance. 展开更多
关键词 Yellow River Basin high-tech industrial agglomeration resource carrying capacity coupling coordination space-time evolution
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Multi-scenario Simulation for 2060 and Driving Factors of the Eco-spatial Carbon Sink in the Beibu Gulf Urban Agglomeration, China 被引量:6
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作者 QIN Menglin ZHAO Yincheng +3 位作者 LIU Yuting JIANG Hongbo LI Hang ZHU Ziming 《Chinese Geographical Science》 SCIE CSCD 2023年第1期85-101,共17页
Since China announced its goal of becoming carbon-neutral by 2060, carbon neutrality has become a major target in the development of China's urban agglomerations. This study applied the Future Land Use Simulation(... Since China announced its goal of becoming carbon-neutral by 2060, carbon neutrality has become a major target in the development of China's urban agglomerations. This study applied the Future Land Use Simulation(FLUS) model to predict the land use pattern of the ecological space of the Beibu Gulf urban agglomeration, in 2060 under ecological priority, agricultural priority and urbanized priority scenarios. The Integrated Valuation of Ecosystem Services and Trade-offs(In VEST) model was employed to analyse the spatial changes in ecological space carbon storage in each scenario from 2020 to 2060. Then, this study used a Geographically Weighted Regression(GWR) model to determine the main driving factors that influence the changes in land carbon sinking capacity. The results of the study can be summarised as follows: firstly, the agricultural and ecological priority scenarios will achieve balanced urban expansion and environmental protection of resources in an ecological space. The urbanized priority scenario will reduce the carbon sinking capacity. Among the simulation scenarios for 2060, carbon storage in the urbanized priority scenario will decrease by 112.26 × 10^(6) t compared with that for 2020 and the average carbon density will decrease by 0.96 kg/m^(2) compared with that for 2020. Carbon storage in the agricultural priority scenario will increase by 84.11 × 10^(6) t, and the average carbon density will decrease by 0.72 kg/m^(2). Carbon storage in the ecological priority scenario will increase by 3.03 × 10^(6) t, and the average carbon density will increase by 0.03 kg/m^(2). Under the premise that the population of the town will increases continuously, the ecological priority development approach may be a wise choice.Secondly, slope, distance to river and elevation are the most important factors that influence the carbon sink pattern of the ecological space in the Beibu Gulf urban agglomeration, followed by GDP, population density, slope direction and distance to traffic infrastructure.At the same time, urban space expansion is the main cause of the changes of this natural factors. Thirdly, the decreasing trend of ecological space is difficult to reverse, so reasonable land use policy to curb the spatial expansion of cities need to be made. 展开更多
关键词 Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model carbon sink multi-scenario simulation ecological space driving factor Beibu Gulf urban agglomeration
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Spatially Heterogeneous Response of Carbon Storage to Land Use Changes in Pearl River Delta Urban Agglomeration, China 被引量:4
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作者 LIU Wei LIU Dianfeng LIU Yang 《Chinese Geographical Science》 SCIE CSCD 2023年第2期271-286,共16页
Carbon storage of terrestrial ecosystems plays a vital role in advancing carbon neutrality. Better understanding of how land use changes affect carbon storage in urban agglomeration will provide valuable guidance for ... Carbon storage of terrestrial ecosystems plays a vital role in advancing carbon neutrality. Better understanding of how land use changes affect carbon storage in urban agglomeration will provide valuable guidance for policymakers in developing effective regional conservation policies. Taking the Pearl River Delta Urban Agglomeration(PRDUA) in China as an example, we examined the heterogeneous response of carbon storage to land use changes in 1990–2018 from a combined view of administrative units and physical entities. The results indicate that the primary change in land use was due to the expansion of construction land(5897.16 km2). The carbon storage in PRDUA decreased from 767.34 Tg C in 1990 to 725.42 Tg C in 2018 with a spatial pattern of high wings and the low middle. The carbon storage loss was largely attributed to construction land expansion(55.74%), followed by forest degradation(54.81%). Changes in carbon storage showed significant divergences in different sized cities and hierarchical boundaries. The coefficients of geographically weighted regression(GWR) reveal that the alteration in carbon storage in Guangzhou City was more responsive to changes in construction land(-0.11) compared to other cities, while that in Shenzhen was mainly affected by the dynamics of forest land(8.32). The change in carbon storage was primarily influenced by the conversion of farmland within urban extent(5.05) and the degradation of forest land in rural areas(5.82). Carbon storage changes were less sensitive to the expansion of construction land in the urban center, urban built-up area, and ex-urban built-up area, with the corresponding GWR coefficients of 0.19, 0.04, and 0.02. This study necessitates the differentiated protection strategies of carbon storage in urban agglomerations. 展开更多
关键词 land use change carbon storage Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model hierarchical urban boundaries Pearl River Delta Urban agglomeration(PRDUA) China
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Experimental study of Al agglomeration on solid propellant burning surface and condensed combustion products 被引量:3
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作者 Cheng-yin Tu Xiong Chen +2 位作者 Ying-kun Li Bei-chen Zhang Chang-sheng Zhou 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第8期111-122,共12页
Aluminum(Al) particles are commonly added to energetic materials including propellants,explosives and pyrotechnics to increase the overall energy density of the composite,but aluminum agglomeration on the combustion s... Aluminum(Al) particles are commonly added to energetic materials including propellants,explosives and pyrotechnics to increase the overall energy density of the composite,but aluminum agglomeration on the combustion surface may lower the combustion efficiency of propellants,resulting in a loss in twophase flow.Therefore,it is necessary to understand the agglomeration mechanism of aluminum particles on the combustion surface.In this paper,a high-pressure sealed combustion chamber is constructed,and high-speed camera is used to capture the whole process of aluminum accumulation,aggregation and agglomeration on the combustion surface,and the secondary agglomeration process near the combustion surface.The microscopic morphology and chemical composition of the condensed combustion products(CCPs) are then studied by using scanning electron microscopy coupled with energy dispersive(SEM-EDS) method.Results show that there are three main types of condensed combustion products:small smoke oxide particles oxidized by aluminum vapor,usually less than 1 μm;typical agglomerates formed by the combustion of aluminum agglomerates;carbonized agglomerates that are widely distributed,usually formed by irregular movements of aluminum agglomerates.The particle size of condensed combustion products is measured by laser particle size meter.As the pressure increases from 0.5 MPa to 1.0 MPa in nitrogen,the mass average particle size of aluminum agglomerates decreases by 49.7%.As the ambient gas is changed from 0.5 MPa nitrogen to 0.5 MPa air,the mass average particle size of aluminum agglomerates decreases by 67.3%.Results show that as the ambient pressure increases,the higher oxygen content can improve combustion efficiency and reduce the average agglomeration size of aluminum particles. 展开更多
关键词 Solid propellant Al particles Condensed combustion products agglomeration Microscopic morphology
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Urban Agglomerations in China: Characteristics and Influencing Factors of Population Agglomeration 被引量:1
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作者 CAO Yongwang ZHANG Rongrong +1 位作者 ZHANG Dahao ZHOU Chunshan 《Chinese Geographical Science》 SCIE CSCD 2023年第4期719-735,共17页
Urban agglomeration(UA)is an advanced spatial economic form formed and developed in the process of rapid industrialization and urbanization,and an important carrier of urbanization and economic development.The economy... Urban agglomeration(UA)is an advanced spatial economic form formed and developed in the process of rapid industrialization and urbanization,and an important carrier of urbanization and economic development.The economy has developed rapidly in the recent decades of China,and the UAs have also developed rapidly.However,as a large population country,the population distribution and changes of UAs in China has unique characteristics.Using the fifth,sixth and seventh population census data,spatial auto-correlation and spatial econometric models,we analyzed the spatial-temporal evolution characteristics and influencing factors of population agglomeration in China’s UAs.Results revealed that:1)from 2000 to 2020,the population gradually converged into UAs,and the characteristics of population agglomeration in different development degree of UAs differ.The higher the development degree of UA,the higher the population agglomeration degree.Besides,UAs are the main area with the most significant population agglomeration degree,and the spatial autocorrelation show that the cities with similar degree tend to be concentrated in space.The urban population gathering in UAs has a certain positive spillover effect on population size of neighboring cities.2)Economic development and social conditions factors are important factors affecting population agglomeration degree in UAs.The main factors of population gather into UAs are similar with the outside UAs,but the positive promotion of urbanization rate and proportion of tertiary industry in GDP on population agglomeration of UAs in China are enhancing from 2000 to 2020.Meanwhile,the other factors,such as high-quality public services,good urban living environment conditions,high-quality medical and educational resources,are also important factors to promote urban population gather into UAs.This study provides a basis for formulating the development planning of UAs in China,and enriches the relevant theoretical research of population evolution and influencing factors of UAs. 展开更多
关键词 urban agglomerations(UAs) population agglomeration influencing factors spatial econometric models China
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The Effect of Urban Agglomeration Expansion on PM_(2.5) Concentrations: Evidence from a Quasi-natural Experiment 被引量:1
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作者 LI Sijia WU Lihua 《Chinese Geographical Science》 SCIE CSCD 2023年第2期250-270,共21页
This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expan... This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expansion on fine particulate matter(PM_(2.5)) concentrations through propensity scores in difference-in-differences models(PSM-DID) using panel data from 286 prefecturelevel cities in China from 2003 to 2016. The results show that 1) urban agglomeration expansion contributes to an overall decrease in PM_(2.5)concentration, which is mainly achieved from the original cities. For the new cities, on the other hand, the expansion significantly increases the local PM_(2.5)concentration. 2) In the long term, the significant influence of urban agglomeration expansion on PM_(2.5)concentration lasts for three years and gradually decreases. A series of robustness tests confirm the applicability of the PSM-DID model.3) Cities with weaker government regulation, a better educated population and higher per capita income present stronger PM_(2.5)reduction effects. 4) Urban agglomeration expansion affects the PM_(2.5)concentration mainly through industrial transfer and population migration, which cause a decrease in the PM_(2.5)concentration in the original cities and an increase in the PM_(2.5)concentration in the new cities.Corresponding policy suggestions are proposed based on the conclusions. 展开更多
关键词 urban agglomeration expansion fine particulate matter(PM_(2.5))concentration quasi-natural experiment propensity scores in difference-in-differences models(PSM-DID) Yangtze River Delta Urban agglomeration China
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Spatial Distribution and Influencing Factors of Urban Shrinkage from the Perspective of Factor Flow - A Case Study of National Urban Agglomerations 被引量:1
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作者 Yuheng Sun Zhifei Ma Huan Huang 《Journal of Architectural Research and Development》 2023年第5期77-85,共9页
This paper examines national urban agglomerations by taking factor flows as the focal point as the research subject.By dividing the stages of urban agglomeration development,a comprehensive framework of urban shrinkag... This paper examines national urban agglomerations by taking factor flows as the focal point as the research subject.By dividing the stages of urban agglomeration development,a comprehensive framework of urban shrinkage is constructed,encompassing economic,population,and social shrinkage.The study explores the spatial distribution characteristics of urban shrinkage during different stages of urban agglomeration and investigates the influencing factors using a geographic detector model.The findings reveal that urban shrinkage within urban agglomerations is widely spread,predominantly in peripheral areas.During the diffusion stage,urban shrinkage is scattered,with population shrinkage concentrated in peripheral regions,economic shrinkage concentrated on old industrial cities,and social shrinkage concentrated on the northeast.The outcomes of the geographic detector model indicate that traffic flow,capital flow,information flow,node importance,network connectivity,government investment,openness,and environmental regulations all play significant roles in shaping the spatial distribution of urban shrinkage. 展开更多
关键词 Urban shrinkage Factor flow National urban agglomeration
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Surface Regional Heat(Cool) Island Effect and Its Diurnal Differences in Arid and Semiarid Resource-based Urban Agglomerations
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作者 CHEN Yan XIE Miaomiao +2 位作者 CHEN Bin WANG Huihui TENG Yali 《Chinese Geographical Science》 SCIE CSCD 2023年第1期131-143,共13页
With the rapid development of urban agglomerations in northwest arid and semiarid regions of China, the scope of the urban heat island(UHI) effect has gradually expanded and gradually connected, and has formed a regio... With the rapid development of urban agglomerations in northwest arid and semiarid regions of China, the scope of the urban heat island(UHI) effect has gradually expanded and gradually connected, and has formed a regional heat island(RHI) with a larger range of impact to the regional environment. However, there are few studies on the heat island effect of urban agglomerations in arid and semiarid regions, so this paper selects the urban agglomeration of Hohhot, Baotou and Ordos(HBO) of Inner Mongolia, China as the study area. Based on the 8-day composite Moderate-resolution Imaging Spectroradiometer(MODIS) surface temperature data(156scenes in all) and land use maps for 2005, 2010, and 2015, we analyze the spatiotemporal distributions of regional heat(cool) islands(RH(C)I) and the responses of surface temperatures to land-use changes in the diurnal and interannual surface cities. The results showed that: 1) from 2005 to 2015, urban areas showed the cold island effect during the day, with the area of the cold island showing a shrinking feature;at night, they showed the heat island effect, with the area of the heat island showing a first decrease and then an increase.2) From 2005 to 2015, the land development(unutilized land to building land) brings the greatest temperature increase(ΔT = 1.36°C)during the day, while the greatest temperature change at night corresponds to the conversion of cultivated land to building land(ΔT =0.78°C) exhibited the largest changes at night. From 2010 to 2015, the land development(grassland to building land) bring the greatest temperature increase(ΔT = 0.85°C) during the day, while the great temperature change at night corresponds to the conversion of water areas to building land(ΔT = 1.38°C) exhibited the largest changes at night. Exploring the spatial and temporal evolution of surface urban heat(cool) islands in urban agglomerations in arid and semiarid regions will help to understand the urbanization characteristics of urban agglomerations and provide a reference for the formulation of policies for the coordinated and healthy development of the region and co-governance of regional environmental problems. 展开更多
关键词 regional heat(cool)island(RH(C)I) urban agglomeration arid and semiarid areas land-use change land surface temperature(LST)
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Spatio-temporal Evolution of Urban Expansion Based on a Novel Adjusted Index and GEE: A Case Study of Central Plains Urban Agglomeration, China
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作者 SU Yanlin LU Chunyan +3 位作者 SU Yue WANG Zili HUANG Yufei YANG Nuocheng 《Chinese Geographical Science》 SCIE CSCD 2023年第4期736-750,共15页
It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of u... It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of urban agglomerations.In this study,a novel vegetation-building-nighttime light-adjusted index(VBNAI)was established for rapid and effective mapping of urban construction land(UCL)in Central Plains Urban Agglomeration(CPUA),China during 2000–2020 based on Google Earth Engine(GEE)platform.Compared with traditional indices,VBNAI can significantly decrease the blooming effect,Normalized Difference Vegetation Index(NDVI)saturation,and soil background of nighttime light data.In addition,the urban expansion indices and standard deviation ellipse model were synthetically adopted to analyze the spatio-temporal evolution pattern of urban expansion.The gravity model and the geographically weighted regression model were employed to determine the spatial interaction forces and drivers of urban expansion,respectively.The results showed that the VBNAI index has obvious advantages in efficiency and accuracy to extract UCL with the overall accuracy of more than 91%.The UCL of CPUA had increased by 4489.84 km2 during 2000–2020 with the gravity center moving towards southeast continuously.From 2000 to 2010,the urban expansion was in a‘center-hinterland’pattern which had benefit from the favorable effect of the traffic shaft belt.During 2010–2020,the urban network structure had basically established.Urban expansion had been influenced by a variety of socio-economic and demographic factors,and the impact degree varied from region to region.This study could provide scientific references for facilitating the intensive utilization of urban resources and optimizing the spatial development pattern of urban agglomeration. 展开更多
关键词 urban expansion urban construction land(UCL)mapping vegetation-building-nighttime light-adjusted index(VBNAI) multi-source remote sensing Google Earth Engine(GEE) Central Plains Urban agglomeration(CPUA) China
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NDVI characteristics and precipitation sensitivity of urban agglomeration in Central Shanxi Basin
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作者 WANG Yue-fei LIU Hai-long +3 位作者 FU Jie LI Yang-jun BAI Xin-qiang TIAN Qing-chun 《Ecological Economy》 2023年第4期359-373,共15页
The overall NDVI characteristics and precipitation sensitivity in the study area from 2000 to 2018 were investigated using NDVI images of urban agglomeration in central Shanxi basin in 2000,2005,2010,and 2018 as well ... The overall NDVI characteristics and precipitation sensitivity in the study area from 2000 to 2018 were investigated using NDVI images of urban agglomeration in central Shanxi basin in 2000,2005,2010,and 2018 as well as the climate data of China’s surface cumulative annual value data set(1981-2010)in accordance with the method such as the geographically weighted regression model.As can be seen from the results,first,the overall NDVI pattern of urban agglomeration in central Shanxi basin,China has been changed and distributed along the topography in the shape of strip.Second,the spatial evolution of NDVI in the study area is varied significantly with the trend of expansion as a whole and a shrinking trend in some areas.Third,the overall precipitation in the study area presents a declining trend from the west to the east,while the NDVI precipitation sensitivity shows a decreasing trend from west to east.To be specific,the west and the east have a positive value of 1.3129 with strong sensitivity and a negative value of-1.0908 with weak sensitivity,respectively.The study results are expected to provide a scientific basis for restoring vegetation and formulating disaster prevention policies for urban agglomeration in Central Shanxi Basin. 展开更多
关键词 NDVl precipitation sensitivity urban agglomeration
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Assessing the impact of manufacturing agglomeration on environmental pollution in Beijing-Tianjin-Hebei region using spatial panel data model
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作者 ZHANG Ting-ting 《Ecological Economy》 2023年第4期374-380,共7页
The Beijing-Tianjin-Hebei region is the vanguard of economic development in northern China.Its manufacturing industry is more and more developed,but environmental pollution is also more serious.Based on the data of 13... The Beijing-Tianjin-Hebei region is the vanguard of economic development in northern China.Its manufacturing industry is more and more developed,but environmental pollution is also more serious.Based on the data of 13 cities in Beijing-Tianjin-Hebei region from 2017 to 2021,the paper verifies the impact of manufacturing agglomeration on environmental pollution.Both manufacturing agglomeration and environmental pollution are dependent on spatial distribution.Therefore,the paper selects spatial econometric model to study.First,the spatial lag model and spatial error model are constructed,and then the spatial lag model is selected through the results of OLS regression,LM Test and Hausman test,and the empirical process is carried out.Finally,the empirical results are analyzed and the conclusion is drawn. 展开更多
关键词 manufacturing agglomeration environmental pollution impact Beijing-Tianjin-Hebei region
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Analysis on the Spatial Agglomeration and Coupling of Socioeconomic Factors in Qinghai Tourism Under the Background of“Belt and Road”
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作者 JU Jian DOU Wenzhang 《Journal of Tourism and Hospitality Management》 2023年第1期1-18,共18页
Qinghai is the strategic base and important fulcrum of the Belt and Road Initiative while tourism is a strategic pillar industry in Qinghai Province.Due to its rich tourism resources and unique ecological environment,... Qinghai is the strategic base and important fulcrum of the Belt and Road Initiative while tourism is a strategic pillar industry in Qinghai Province.Due to its rich tourism resources and unique ecological environment,the integration of tourism in Qinghai into the Belt and Road has attracted great attention of the Asian Development Bank(ADB).With the spatial data of tourism elements POI and the statistical data of 44 counties in Qinghai to analyze the characteristics and influencing factors of the spatial agglomeration of tourism in Qinghai,the paper conducts research on spatial coupling and concludes with the following results:The spatial agglomeration of tourism in Qinghai presents the distribution pattern of“one circle and one belt”;economic density and population density play an important role in the formation of the spatial agglomeration pattern of tourism with some spatial spillovers;Belt and Road has a significant impact on the promotion of tourism agglomeration in Qinghai.The paper suggests that tourism in Qinghai should fully integrate into the Belt and Road,giving full play to the guiding role of Belt and Road in the allocation of social and economic resources,and optimizing the spatial layout. 展开更多
关键词 Belt and Road tourism in Qinghai spatial agglomeration spatial econometrics model
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